The invention relates to a wristwatch of the type in which a hollow cylindrical seal is disposed within an outer casing. The watch crystal and bottom cover are mounted within the seal, the seal being formed of a hard synthetic plastic. The bottom cover includes an upright wall against which a radial collar of the watch movement bears. Such an arrangement is disclosed in U.S. application Ser. No. 06/584,339, filed Feb. 28, 1984, now U.S. Pat. No. 4,548,514.
In such a case, complications might arise during assembly because the collar on conventional watch movements does not project radially very far. By providing even a slight radial tolerance between the wall and the movement, it is possible that an inadequate engagement between the wall and collar may occur, especially if the cover is inserted in a skewed manner, i.e., tilted with respect to the axis of the seal. Furthermore, such an arrangement wherein the watch movement telecopes into the wall of the cover is very expensive to fabricate in cases where the watch movement has a non-circular cross-sectional shape.
It is readily possible to insert between the collar of the movement and the wall of the bottom cover a conventional bottom ring which protrudes radially beyond the wall and can be conveniently provided with an internal diameter which corresponds to the geometry of the watch movement. This accommodates a greater radial tolerance between the movement and the wall of the cover, but also is more costly in terms of parts and their assembly. In addition, the radial dimension of the seal and thus the outer case is undesirably increased in such an instance.
It is, therefore, an object of the invention to provide an arrangement in which a proper orientation of the watch movement is assured and is not dependent upon the orientation of the bottom cover.
Another object is to minimize the radial dimension of the seal and outer case.
An additional object is to minimize the cost of the watch.
Yet another object is to multiply the number of possible uses for a seal of the above-mentioned type.
One further object is to simplify the manufacture and assembly of a watch mechanism of that type.